The invention relates to a method for the pre-baking treatment of shaped and frozen bread dough.
Shaped and frozen bread dough is usually taken out from a freezer or a refrigerated warehouse, and thawed out in a room(a room temperature method) or in a proofer (a thawing and proofing method). After the completion of thawing, dough with a temperature of between 0xc2x0 C.xcx9c20xc2x0 C. is put in a proofer for a final proofing process.
Recently, a thawing method using a retarder is adopted for relieving workers of their early morning shift, in which the thawing process is carried out for 6xcx9c24 hours at a temperature range of 0xc2x0 C.xcx9c5xc2x0 C. Further, a dough conditioner is now used in which the retarder is equipped with a computer system, enabling a continuous and automated processes of thawing and final proofing.
Japanese Patent Publication Hei.6-36707 discloses a thawing method, comprising heating shaped and frozen bread dough for 2xcx9c6 hours up to a temperature of 10xc2x0 C. at an average temperature-raising rate of 0.07xcx9c0.28xc2x0 C. /min and a relative humidity of 70xcx9c100%, and further keeping it for 10 minxcx9c6 hours at a temperature of 10xc2x0 C.xcx9c20xc2x0 C. and a relative humidity of 70xcx9c100%.
Japanese Patent Application Laid Open Hei.5-64539 discloses a bread-making method, comprising thawing with retardation frozen bread dough for 10 minxcx9c72 ours at a temperature of xe2x88x925xcx9c10xc2x0 C. /min, a relative humidity of 90xcx9c100% and ventilation rate of 0.2 m/s or less, pre-heating it for one hour and 20 min xcx9c2 hours and 10 min up to a temperature of 15xcx9c20xc2x0 C., heating it for 20 minxcx9cone hours and 10 min up to a temperature of 22xcx9c40xc2x0 C., keeping it for 20 minxcx9c3 hours at the same temperature, and then baking the bread dough.
Japanese Patent Application Laid Open Hei.7-155100 discloses a method of keeping bread in a suitable condition for baking for a long period of time, comprising keeping the bread at a temperature of 0xcx9c18xc2x0 C. after final proofing in order to inhibit the activity of bakers"" yeast.
Japanese Patent No. 2729669 discloses a method for the pre-baking treatment of frozen bread dough comprising adjusting a thawing condition for each of different kinds of bread that need different time for their final proofing, so that their final proofing may be done simultaneously.
The purpose of the present invention is first to simplify complicated pre-baking work, secondly to standardize the pre-baking work of various kinds of bread dough in order to simultaneously carry out their pre-baking, and finally to increase baking frequency of bread dough.
By utilizing shaped and frozen bread dough, it will be possible to simplify the work in a bakery and to significantly reduce the workload, when compared with a conventional scratch baking method wherein all the processes from mixing to baking are continuously in store. Without a professional baker or artisan having a specialized technique, it would be therefore possible to make bread.
However, even if the shaped and frozen bread dough is used at a usual bakery where 60xcx9c100 kinds of bread are made, they can not be produced more than twice per day so that freshly baked bread can hardly be always provided to customers all the day.
The reasons for that may be as follows, for example:
First, since the conventional thawing methods need plenty of time, it would be very hard to be carry out several times in a day; second, since each kind of bread items needs different time for their thawing and final proofing processes, an individual treatment will be required for each kind of bread. As a result, the number of the working processes and working frequency will be increased and working processes will be more complicated as the number of the bread items are increased; and the finally proofed bread dough has to be baked immediately.
It is therefore desirable to simplify the working for bread making by continuously carrying out thawing and final proofing processes, and keeping the finally proofed bread dough for a certain period of time so that baking can be done at any time.
The present invention relates to a method for the pre-baking treatment of shaped and frozen bread dough, comprising is continuously carrying out a thawing process and a final proofing process of the shaped and frozen bread dough in a container while keeping its inner temperature at a range of 17xcx9c40xc2x0 C., preferably of 22xcx9c35xc2x0 C. and its inner relative humidity at a range of 50xcx9c75%, preferably of 60xcx9c65%, and after the completion of the final proofing, putting the bread dough in another container with its inner temperature at a range of xe2x88x9220xcx9c15xc2x0 C. and its inner relative humidity of 80% or more so that the condition of the bread dough may be maintained.
The present invention is also related to a method for the pre-baking treatment of shaped and frozen bread dough, comprising continuously carrying out a thawing process and a final proofing process of the shaped and frozen bread dough in a container while keeping its inner temperature at a range of 17xcx9c40xc2x0 C., preferably of 22xcx9c35xc2x0 C. and its inner relative humidity at a range of 50xcx9c75%, preferably of 60xcx9c65%, and after the completion of the final proofing, lowering its inner temperature to a range of xe2x88x9220xcx9c15xc2x0 C., preferably of 0xcx9c10xc2x0 C. at a lowering rate of 0.2xc2x0 C./min or more, preferably 0.4xc2x0 C./min or more while controlling the difference between a dew point in the container and a temperature on the bread surface within 20xc2x0 C. or less, preferably 15xc2x0 C. or less more so that the condition of the bread dough may be maintained.
According to the present invention, it is possible to continuously carry out the thawing and final proofing processes of the shaped and frozen bread dough by putting the bread dough in a container whose inner temperature and relative humidity have already been set at desired ranges without necessity of any further change of its temperature or relative humidity thereafter.
An xe2x80x9cinner relative humidityxe2x80x9d means that of air in the container and is an average value subjected to fluctuation at a range of about xc2x110%. According to the present invention, the temperature or relative humidity in the container is not necessarily kept at a constant level, as long as they are kept at the above ranges.
Alternatively, the continuous processes of thawing and final proofing of the present invention may be carried out by raising its inner temperature to a range of 17xcx9c40xc2x0 C., preferably of 22xcx9c35xc2x0 C. at a raising rate of 0.1xcx9c2xc2x0 C./min, preferably 0.3xcx9c1xc2x0 C./min while controlling the difference between a dew point in the container and a temperature on the bread surface within 20xc2x0 C. or less, preferably 15xc2x0 C. or less.
In the above case, it is not necessary to keep the container with its inner temperature at a range of 17xcx9c40xc2x0 C., or to control the difference between a dew point in the container and a temperature of the bread surface within 20xc2x0 C. or less at the time of putting the bread dough in it. Thus, the bread may be put in the container with its inner temperature at a range of xe2x88x9220xcx9c15xc2x0 C. and the difference of 20xc2x0 C. or more between a dew point in the container and a temperature of the bread surface.
According to the present invention, the bread dough that is ready for baking can be made within about 2xcx9c4 hours from the starting of thawing through the continuous processes of thawing and final proofing in the same container.
The raising rate is not necessarily kept at the same level during the raising period, but may be varied within the above range. Thus, the raising rate may change continuously or gradually. Further, after the temperature in the container has been raised to a certain level, it may be kept within the above range to continue the final proofing process.
Conventional thawing processes under a high temperature have disadvantages of the occurrence of dampness on the bread surface during the thawing process and irregularity in thawing.
According to the present invention, however, it is possible to inhibit the generation of dampness on the bread surface during the thawing process by keeping a relative humidity at a range of 50xcx9c75% in the container or by controlling the difference between a dew point in the container and a temperature on the bread surface within 20xc2x0 C. or less. And a high raising rate of the temperature according to the present invention can rapidly heat the center of the bread dough, especially in a small piece of the shaped and frozen dough, reducing the difference in the activity of bakers"" yeast between in the center and on the surface of the bread dough so that the above problem of irregularity in thawing is improved to give bread with an excellent quality.
It is known in the art that white spots named xe2x80x9ca fish eyexe2x80x9d will appear on the surface of the baked bread if it has been kept at a temperature of 0xcx9c15xc2x0 C. for a long time. Such fish eyes may often be also observed after thawing of the shaped and frozen bread dough.
However, a rapid thawing within such a short period of time as a few hours according to the present invention does not show the above phenomena so that the surface of the bread will be in an excellent condition.
Further, according to the present invention, it is possible to rapidly inhibit the activity of bakers"" yeast in the bread by putting the bread dough to another container with its inner temperature at a range of xe2x88x9220xcx9c15xc2x0 C. and its inner relative humidity of 80% or more after the completion of the final proofing, or by lowering the inner temperature to a range of xe2x88x9220xcx9c15xc2x0 C., preferably of 0xcx9c10xc2x0 C. at a lowering rate of 0.2xc2x0 C./min or more, preferably 0.4xc2x0 C./min or more while controlling the difference between a dew point in the same container and a temperature on the bread surface within 20xc2x0 C. or less.
As a result, it is possible to minimize the change in the condition of the bread, especially that in its volume, so that the bread dough may be maintained in an excellent condition after the final proofing for a long time without showing any dryness on its surface.
The lowering rate is not necessarily kept at the same level during the lowering period, but may be varied within the above range. Thus, the lowering rate may change continuously or gradually.
The difference between a dew point in the container and a temperature of the bread surface according to the present invention is an average value and subjected to fluctuation at a range of about xc2x110%.
The above difference may be determined by any method known to those skilled in the art. For example, the dew point of air may be obtained from a psychrometric chart that shows a relationship between a temperature and humidity, and the temperature on the bread surface may be actually measured by means of a known temperature sensor.
An apparatus which may be used in the present invention for thawing, final proofing, and keeping the bread dough under cooling after the final proofing is generally called a xe2x80x9cdough conditioner,xe2x80x9d in which heating, cooling, humidifying, and dehumidifying may be optionally done. Especially, it is desirable to use a dough conditioner having a cooling power of more than 400 W, preferably more than 600 W and a heating power of more than 600 W, preferably more than 1 KW per 20 Kg of frozen bread dough. Any other type of dough conditioners known in the art may be used in the present invention.
Further, the present invention is related to a method for the pre-baking treatment of shaped and frozen bread dough, characterized in that an amount of bakers"" yeast to be added to each piece of a plural kind of the shaped and frozen bread dough is adjusted so that a total time of the thawing and final proofing processes for each of the above bread dough may be uniformed.
It is known that the composition of bread dough varies very much depending on a kind of the bread. Even if the same amount of bakers"" yeast is added, the degree of the activity of the bakers"" yeast will be significantly influenced by the composition, especially by the content of salt and sugars, and an amount of generated CO2 gas (or a CO2 generating rate) will vary in a great degree.
An optimum dough-swelling rate in the final proofing process, in other words, an optimum amount of the generated CO2 gas is different depending on a kind of the bread. Furthermore, the thawing rate is different depending on the shape or amount of divided bread dough.
According to the present invention, an amount of the generated CO2 gas is measured for each kind of the bread dough by means of a fermograph in order to calculate an amount of the bakers"" yeast that will generate a necessary amount of CO2 gas in a certain period of time. Based on the calculated values, an amount of the bakers"" yeast to be added is adjusted for each kind of the shaped and frozen bread dough so that a total time of thawing and final proofing for each piece of the plural kind of the bread dough may be uniformed.
There is no limitation with respect to materials used for the present shaped and frozen bread dough and their content ratios. For example, those skilled in the art may optionally select them depending on the kind of final products including sweetened buns such as bean-filled ones and butter roll.
Starting bread dough prepared by optionally mixing various materials may be subjected to well known processes such as pre-treatment, mixing, kneading, and proofing, then dividing, rounding, dry-proofing, molding, and shaping, followed by freezing by means of a freezer such as an xe2x80x9cair blast freezerxe2x80x9d and keeping in the freezer and the like at an appropriate temperature.
The shape of the frozen bread dough may be optionally selected by those skilled in the art depending on the kind of the final products.